Portable computer apparatus with thermal enhancements and multiple modes of operation

ABSTRACT

A portable computer adapted for electrical connection to a docking station having multiple power modes of operation is described. The portable computer has one or more CPU chips which have at least two power modes of operation, a low power mode and a high power mode. When the portable computer is operated as a stand-alone computer, it operates in the low power mode. When the portable computer is operated while electrically connected to the docking station, it operates in a high power mode. The docking station has greater cooling capacity than the portable computer alone to provide enhanced cooling of the high power mode of operation.

FIELD OF INVENTION

The present invention is directed to portable computers having at leasttwo power modes of operation. In particular, an embodiment of thepresent invention is directed to a portable computer having a high andlow power mode of operation and more particularly in association with adocking station wherein the portable computer operates in a lower powermode when not engaged in the docking station and in a high power modewhen engaged in the docking station which has cooling systems to coolthe high power mode of operation.

BACKGROUND

The power consumption of laptop computers, especially the power of CPUsused in laptop computers is increasing. For instance, the total power ofa laptop computer is usually around 10 watts and now it is becoming 20to 30 W. The CPU power has been increased from 2 to 8 W and in thefuture could be in the 15 W range and higher. Most of this power willeventually be dissipated as heat to the surroundings. Getting more heatout of the laptop computer is becoming a critical factor in the laptopcomputer business.

Portable computers, such as laptop computers, are designed to be compactand small. Thus there is limited space to incorporate cooling systems.Thus portable computers cannot operate using the fastest CPU chipsavailable. This presents a problem when the portable computer is used asa workstation, as a desk top computer or in place of a desk topcomputer. Typically a portable computer is used as a workstation byinserting the portable computer into a frame, referred to as a dockingstation. The docking station provides additional functionality to theportable computer, such as additional disk drives and CD drives. Thedocking station has ports through which a large keyboard and a largescreen monitor can be connected to the portable computer. The portablecomputer when engaged with a docking station and used as a workstationhas the disadvantage as compared with a desktop computer of notfunctioning as fast as the desktop computer. This is because the desktopcomputer has a cooling system which can cool the desktop computer whichhas a CPU which runs too hot to be included in the portable computer.Applications running on the portable computer engaged with a dockingstation have slower performance than the desktop and some applicationseither cannot run on the in a portable computer engaged with dockingstation or run so slow as to be effectively unusable. Applicantsinvention solves this problem.

A portable computer is intended to be transported around by a user. Asdescribed above, the portable computer is commonly used as a workstationby inserting into a docking station. A user typically has a dockingstation in their office and typically takes the portable computer onbusiness or for use at home. If the user takes the portable computerhome and forgets to bring it into the office, the user has no computerto use in the office. This prevents the user from accessing systems suchas e-mail, the internet and using word processors. Applicants inventionsolves this problem.

SUMMARY

A broad aspect of the present invention is a system having: a portablecomputer; a docking station; the portable computer has a low power modeof operation and a high power mode of operation; and, a sensor forsensing if the portable computer is engaged in the docking station or ifthe portable computer in not engaged in the docking station.

Another broad aspect of the present invention is a system having: aportable computer; a docking station; the portable computer comprises alow power mode of operation and a high power mode of operation; and, asignal generator for switching the computer between the high power modeof operation and the low power mode of operation.

Another broad aspect of the present invention is a system having: acomputer; the computer has a low power mode of operation and a highpower mode of operation; and, a signal generator for switching saidcomputer between the high power mode of operation and the low power modeof operation in response to an input.

Another broad aspect of the present invention is a system having: aportable computer; a docking station; the portable computer has a firstCPU; the docking station has a second CPU; and the docking stationwithout the portable computer engaged to the docking station is operablethrough the second CPU.

Another broad aspect of the present invention is a system to increasethe cooling capability of a portable computer when it is in a dockingbase.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features and advantages of the presentinvention will become apparent upon a consideration of the followingdetailed description and the invention when read in conjunction with thedrawing Figures, in which:

FIG. 1 is the schematic view of a laptop computer sitting on a tray of adocking base waiting to be docked.

FIG. 2 is the schematic view of a laptop computer docked into the base.

FIG. 3 is the schematic view of a laptop computer docked into the baseenhanced with a thermo-electric cooler.

FIG. 4 is the schematic view of a laptop computer docked into the basewith an air flow booster.

FIG. 5 is a schematic diagram of a heat-spreader useful with the presentinvention.

FIG. 6 schematically shows a portable computer with a CPU having a clockinput and an input to control the clock to change the power mode of theCPU.

FIG. 7 schematically shows a portable computer having more than one CPU.

FIG. 8 schematically shows a portable computer engaged in a base stationwith peripheral devices attached.

FIG. 9 schematically shows a portable computer and base station whichhas its own CPU.

DETAILED DESCRIPTION

A portable computer is commonly referred to as a laptop computer andboth terms will be used interchangeably herein.

Referring to FIG. 1, a laptop computer 10 has a printed wiring board 11to which a CPU chip 12 is connected. A heat sink 13 is mounted on thetop of the CPU chip 12. When the laptop computer is powered on heatgenerated in the CPU chip 12 is dissipated through the heat sink tooutside of the laptop computer 10. An optional cooling fan 14 can beadded to the top of the heat sink to boost its cooling capability.Because of the limitations of space and battery power in the laptopcomputers, the cooling fan 14 is generally small and has limited coolingpower. The laptop computer can be docked into a base station 31 to getpower and signal connections as well as other input/output extensions.FIG. 1 shows a laptop computer 10 with its display 18 in the closedposition sitting on a sliding tray 21 waiting to be docked into the basestation 31. (The term base station and docking station are usedinterchangeably herein. FIGS. 1-4 show an exemplary embodiment of a basestation.) Both the laptop computer 10 and the base station 31 haveconnectors for electrical connection and will be interlocked togetherwhen the tray 21 is slid into the base station 31. These electricalconnectors are typically on the side 15A of the laptop 10 which ispressed against a portion 15B of the docking station 31. Typically, theportable computer has an electrical connector which makes and engageswith a connection on the docking station. These connectors are comingknown in the art. The figure shows a means to provide coolingenhancement of the laptop computer 10 when it is docked into the basestation 31. The heat conduction member 34 is mounted inside the basestation 31. A heat sink 32 is placed in good thermal contact with theheat conduction member 34. A cooling fan 33 is attached to the end ofthe heat sink 32. Because the base station is usually powered by an ACpower line and has larger housing, the size of heat sink 32 and thecooling fan 33 can be much larger than those in the laptop computer. Asa result, their cooling capability is much higher than that of those inthe laptop computer. In an exemplary embodiment, when the laptopcomputer 10 is docked and its display 18 is in the open position withthe keyboard 19 exposed as shown in FIG. 2, the heat conduction member34 will engage with the heat sink 13 in the laptop computer 10. Theclamp-like member 15 on the heat sink 13 will ensure that the heatconduction member 34 is in good thermal contact with the heat sink 13.The cooling fan 33 will be turned on once the laptop computer 10 isfully docked. The cooling fan 33 will then pull the air in from theinlet 41 and force the air passing through the heat sink 32. The hot airwill exhaust from the outlet 42. The arrows in the figure show the airmoving direction as described. However, the direction of air movementcan be designed to any ways to get the best cooling effects. The heatconduction member 34 is made of heat conductive materials such as copperor aluminum. A heat pipe can be embedded in the heat conduction member34 to reduce the thermal resistance from the heat sink 13 to the heatsink 32.

The cooling capability of the laptop computer can be increased furtherwhen it is docked into the base station with a thermo-electric coolerinstalled. As shown in FIG. 3, The thermoelectric cooler 35 is insertedbetween the heat conduction member 34 and the heat sink 32. Athermo-electric cooler is a well-known device in the field that usesPeltier effect to pump heat away from one side to the other when anelectric current is applied. The thermo-electric cooler in this setupwill help to improve the heat flow from the CPU chip 12 to the heat sink32. If the heat pumping power of the thermo-electric cooler is largeenough, the temperature of the CPU chip 12 can be brought down to closeto or even below ambient room temperature. This is sometimes desirablesince lowering the CPU temperature will increase its reliability andperformance. However, since the heat pumping efficiency of thethermoelectric cooler is about 0.6 or below, the cooling capability ofthe heat sink 32 must be designed accordingly to dissipate the extraheat generated from the thermo-electric cooler.

FIG. 4 shows another embodiment of the current invention of thermalenhancement of a laptop computer when it is docked in a base station.The laptop computer 110 is sitting on a sliding tray 121 on a basestation 131. The figure also shows the keyboard 119 and the display 118in the open position. Inside the laptop computer 110, the CPU chip 112is connected on a printed wiring board 111. A flat unidirectionalcooling fan 114 is mounted on top of the CPU chip 112. Air is coming infrom the fan inlet 123 and exiting from the fan outlet 124. One exampleof this flat unidirectional fan is Panasonic Model UDQFC3E04. Because ofthe size of the fan is limited by the space available in the laptopcomputer 110, the amount of air movement and hence the cooling power islimited. When the laptop computer 110 is docked, however, the amount ofair moving will be increased by connecting the unidirectional fan 114 toanother relatively high-power fan 133 inside the base station 131. Moreair passing the fan 114, the more is its cooling power. An elastomerseal 115 is used to prevent any air leakage during docking.

FIGS. 2-4 show portable computer 12 inserted into base station 31 withthe portable computer in the open position so that the portable computerscreen and keyboard are exposed and available for use by a user.Alternatively, a larger standalone keyboard and display can beelectrically connected to the base station by means of cables pluggedinto sockets on the base station.

FIG. 5 shows another embodiment of a mechanism for engaging anddisengaging a portable computer from thermal connection to an apparatusfor dissipating heat which is part of the base station.

In FIG. 5, the head spreader 213, which is in good thermal contact witha heat generating semiconductor chip package such as a CPU (not shown inthe figure), is enhanced with two heat pipes 251 and 252. Heat spreader213 corresponds to the thermal clamp 15 of FIG. 1. One end of the heatpipes 251 and 252 are embedded near the tip of the heat spreader 213.The heat pipes are placed in parallel with the grooves 253 and 254. Theheat spreader 213 are housed in a laptop computer. When the laptopcomputer is docked, the heat spreader 213 will be forced in between thetwo rotors 291 and 292 which are part of the receiving mechanism in thedocking station. While in the docking position, the rotor 291 will be inthe groove 253 and the rotor 292 will be in groove 254. In FIG. 5, theheat spreader 213 is on the left side and the receiving mechanism andthe heat sink are on the right hand side. Two heat pipes 261 and 262 areused to carry the heat received from the rotors 291 and 292 to the heatsink 232. The rotors 261 and 262 are held by the supporters 271, 272,273 and 274, respectively. The rotors 261 and 262 are free to rotatealong the common axis defined by the supporters. The tip portion of theheat pipes 261 and 262 is placed inside the rotors 292 and 292 coincidedwith their common axis, respectively. Lubrication greases are addedwithin the rotors to improve heat transfer from the rotors to the heatpipes and also reduce the friction between them. The supporters 271,272, 273 and 274 are in turn supported by the holders 275, 276, 277 and278, respectively. The holders 276 and 277 are mounded on one side ofthe bottom plate 234 and free to rotate along their common anchor point288. The rotational angle of holders 276 and 277 are constrained by thetwo stoppers 285 and 286 and the two strip springs 281 and 282 whichwill provide the needed clamping force to the two rotors 291 and 292while in the docking position. Similar arrangement applied to the twoholders 275 and 278. The other end of the heat pipes 261 and 262 areplaced under the heat sink 232. There are two ways to join this part ofthe heat pipes to the bottom plate 234. If the heat pipes are long andflexible enough, the heat pipes can be soldered or epoxied to the bottomplate 234. If the heat pipes are too rigid to bend, the heat pipes areinserted into holes filled with lubrication greases and allowed torotate when the rotors 291 and 292 move during docking. A cooling fanwhich is not shown in the figure can be mounted on the heat sink 232 toboost its cooling capacity.

Chip 12 of FIGS. 1-3 and chip 112 of FIG. 4 are preferably a CPU chiphaving at least one low power mode of operation and at least one highpower mode of operation. When chip 12 is referred to herein, unlessstated otherwise, since chip 112 is analogous. Thus comments about chip12 also apply to chip 112. An example of a chip useful to practice thepresent invention is Intel® Chip 2371AB (Trademark of Intel Corp.) whichis described in documentation available from Intel Corporation datedApril 1997 with order number: 290562-001, the teaching of which isincorporated herein by reference. This chip is a control chipcontrolling the CPU/memory, peripherals and busses. the descriptionbelow refers to CPU chip 12 having inputs to control the speed at whichthe chip runs. This can be done using a control chip such as the Intelchip. FIG. 6 schematically shows portable computer 10, having CPU chip12 which has clock input 400 and a throttle control input 402 which isused to control the duty cycle of the clock or the amount of time forwhich the clock is on and thus the power consumption of chip 12.Circuitry is provided in the portable computer 10, for example on chip12 (schematically shows as dashed box 404), which senses whether or notthe portable computer 10 is inserted or not inserted into electricalengagement with base station 31. Such sensing circuits are commonly usedin the art. (Optionally, the sense circuit can be on another elementsuch as chip 406 which is electrically connected as indicated by 408 tochip 12. Elements 406 and 408 are shown dashed in the FIG. 6 since theyare optional.) For example, when a computer is turned on, a test is doneto determine which peripheral devices, such as a keyboard, display and aprinter, are attached thereto. Also, a peripheral device can beelectrically connected to a computer which is in the on mode. Forexample, a cable from a printer can be inserted to a port on thecomputer which is provided for electrically connecting a peripheraldevice. When this happens, the computer senses that the peripheraldevice is electrically connected, the peripheral device is initializedand the computer can send and receive data to and from the peripheraldevice. Such commonly available circuitry can be used by the portablecomputer 10 to sense the electrical connection to the base station 31.When the circuit senses that the portable computer 10 is electricallyconnected to the base station 31, a signal is provided to switch thechip 12 from the low power to the high power mode of operation. TheIntel 82371AB has a system throttle control which permits this chip tobe toggled. The Intel 82371AB system throttle control has an input(THTL_DTY) which is programmed to control the duty cycle of the inputclock signal to the chip 12 which is controlling the speed of chip 12.By controlling the duty cycle at which the chip 12 functions at, thepower dissipated by the chip can be controlled. When the portablecomputer 10 is not in electrical connection with the base station 31,this input can be set for a low power mode of operation. When theportable computer 10 is inserted in electrical connection with the basestation 31, this input can be set for a higher power mode of operation.

As described above, the additionally heat generated as a result of thishigher power mode of operation is dissipated by the cooling mechanismprovided with the base station.

Alternatively, the chip 12 can have a clock input which can be modifiedby setting an input to the chip 12. For example, the clock input can bemultiplied by a predetermined amount so that the clock rate of the chip12 can be set to be at a low clock rate which corresponds to a low powermode of operation or at a high clock rate which corresponds to a highpower mode of operation. (Different multipliers correspond to differentpower levels.) Chips having an input to set the multiplier between atleast two values are currently available. For example, Intel® Pentium®Processor With MMX™ Technology (Trademarks of Intel Corp.) which isdescribed in documentation available from the Intel Corp. dated June1997 Order Number 243185.004 the teaching of which is incorporatedherein by reference The inputs BF1 and BF2 are set to a 0 or 1 value toselect from a number of modes of operation. The sense circuit whichsenses whether or not the portable computer 10 is in electricalengagement with the base station 31, results in setting the input to thechip 12 to change the degree of multiplication and thereby the clockrate at which the chip 12 operates.

Alternatively, such as schematically shown in FIG. 7, the portablecomputer 10 can have a first CPU chip 12 which operates at a low powerand can have a second CPU chip 12 which operates at a high power mode(or any number of CPUs to operate in many different power modes). Whenthe portable computer 10 is not in electrical engagement with the basestation 31, the low power CPU chip 12 controls the function of theportable computer 10. When the portable computer 10 is inserted inelectrical engagement with the base station 31, the high power chipcontrols the operation of the portable computer 10. The sense circuitwhich senses whether or not the portable computer 10 is inserted inelectrical engagement with the base station 31 selects whether the highpower mode chip or the low power mode chip controls the function of theportable computer 10.

In an alternative embodiment, the circuit which senses whether theportable computer 10 is in electrical engagement with the base station31, can be in the base station 31. FIG. 8 schematically shows basestation 31 in electrical engagement with portable computer 10 throughelectrical connection of electrical connector 412 on base station 31 toelectrical connector 410 on portable computer 10. FIG. 8 also showsoptional electrical connection of peripheral devices 414, 416 and 418 byelectrical connections 420, 422 and 418, respectively to base station31. The peripheral devices can be any devices, such as a keyboard,display, printer, LAN connection, modem, telephone system connection,and internet connection. Sense circuit 426 shown as a dashed box isoptionally in base station 426. Base station 31 has thermal coupling 427and portable computer has thermal coupling 428. Thermal couplings 427and 428 are disengageable for thermally connecting and disconnectingbase station 31 and portable computer 10. Examples of thermal couplings427 and 428 are given above. When the portable computer 10 is engagedelectrically with the base station 31, the sense circuit of the basestation 31 sends a signal to the chip 12 through the electricalconnection between the portable computer 10 and the base station 31. Thesignal places the chip 12 in the high power mode of operation or resultsin the selection of the high power mode chip. The sense circuit when itis in the portable computer 10 can optionally be on the chip 12 or ispart of another component such as another chip which is electricallyconnected to the chip 12. Alternatively, a user of the system can, byentering an appropriately designed set of key strokes at the keyboard,change the mode of operation at which the chip 12 operates.

FIG. 9 shows portable computer 10 and base station 31. The base station31 has its own CPU 430. The CPU 12 of the portable computer 10 can be alow power CPU which can control the function of portable computer 10when it is not engaged in electrical connection with base station 31.Base station 31 can have its own CPU 430 which can be a high power CPU.Either base station 31 or portable computer 10 can have sense circuit tosense whether portable computer 10 is electrically engaged or not tobase station 31. When the portable computer 10 is electrically engagedwith base station 31, high power chip 430 controls the operation ofportable computer 10. The circuitry to switch control from low powerchip 12 to high power chip 430 can be either in the portable computer 10or base station 31. Alternatively, chip 12 can be a chip as describedabove having at least a high and low power mode of operation. (Such achip can have a plurality of modes of operation) and chip 430 can be aCPU chip sufficient to provide the base station 31 with minimalfunctionality or the chip 430 can have any desired degree offunctionality. For purposes of minimal cost, chip 430 is preferably achip which provides sufficient functionality to the base station 31 sothat the base station 31 without the portable computer electricallyengaged to it has a degree of functionality sufficient for the basestation alone to provide a user with some useful function. For example,if a user forgets to bring the portable computer to the location of basestation 31 such as when a user brings portable computer 10 home from theuser's office and forgets to bring the portable computer 10 back to theoffice when the user returns to the office, base station 31 aloneprovides the user with some limited functions. An exemplary list oflimited functions which the base station 31 alone can provide are e-mailaccess, connection to the internet and word processing capability. Sucha base station permits a user to perform work assignments without thefull work station capability provided by the portable computer-basestation combination.

Additionally, the power mode of CPU 12 or CPU 426 can be controlled bythe temperature of the CPU. The clock throttling signal and/or clockfrequency can be adjusted to run the CPU according to the maximumallowable temperature of the CPU as described above and provided byIntel® Chip 82371AB.

While this invention has been described in terms of certain embodimentthereof, it is not intended that it be limited to the above description,but rather only to the extent set forth in the following claims. Theembodiments of the invention in which an exclusive property or privilegeis claimed are defined in the appended claims. The teaching of allreferences cited herein are incorporated herein by reference.

1. an apparatus comprising: a portable computer; a docking station; saidportable computer comprises a low performance mode of operation and ahigh performance mode of operation; a sensor for sensing if saidportable computer is engaged in said docking station or if said portablecomputer is not engaged in said docking station; both said high and saidlow performance modes of operation are actively user usable modes ofoperation; a signal generator for switching said computer between saidhigh performance mode of operation and said low performance mode ofoperation in response to an input; said input being selected from thegroup consisting of an output of said sensor indicating that saidportable computer is engaged with said docking station and for switchingsaid portable computer into said high performance mode of operation andan output of a temperature sensor which monitors the operatingtemperature of said computer to switch said computer between said highperformance mode of operation and said low performance mode ofoperation; said portable computer comprises a low performance CPUcomprising said low performance mode of operation and a high performanceCPU comprising said high performance mode of operation; said portablecomputer comprises a portable computer cooling system; said dockingstation comprises a docking station cooling system for engagement anddisengagement with said portable computer cooling system for enhancedcooling of said portable computer when engaged with said docking stationand operating in said high performance mode of operation and for reducedcooling of said portable computer when disengaged from said dockingstation and operating in said low performance mode or operation; andsaid engaged cooling system comprises a first air blower in saidportable computer coupled to a first air port in said portable computerand to a heat sink in said portable computer, a second airport in saiddocking station coupled to a second air blower in said docking station,said first airport is disposed adjacent to and in substantially airtightengagement with said second airport through an elastomeric seal betweensaid engaged first and second airports to substantially prevent airleakage from said substantially airtight engagement, a third air port onsaid docking station having a cross sectional area larger than a crosssectional area of said second air port, said engaged cooling system hasa higher air flow capacity through said portable computer when operatingin said high performance mode of operation from said high performanceCPU than the maximum air flow capacity provided by said first air blowerto said portable computer when operating in said low performance mode ofoperation from said low performance CPU, the second air blower having asubstantially higher air handling capacity than said first air blower bythe combination of said second air port and said third air port, by thesecond cross sectional area being greater than said first crosssectional area and by said second air blower having a higher airhandling capacity than said first air blower.